Annotation and Labeling Guide AI Prompt

Design the annotation and labeling strategy for this chart.

Chart type: {{chart_type}}
Key insight to communicate: {{key_insight}}
Audience: {{audience}}

1. Title and subtitle strategy:
   - Title: state the insight, not the data. 'Revenue grew 34% in Q3' beats 'Quarterly Revenue.'
   - Title should be answerable by 'so what?' — not just 'what is this?'
   - Subtitle: add essential context (time period, geography, unit, data source)
   - Format: title bold and prominent, subtitle smaller and lighter

2. Axis labels:
   - Label axes only when the unit is not obvious from the title or context
   - Remove redundant axis label if values are labeled on the chart directly
   - Rotate x-axis labels only as a last resort — prefer angled labels or flipping to horizontal bar chart
   - Units belong on the axis label or in parentheses, NOT repeated on every tick

3. Data labels (value annotations on data points):
   Guideline: use data labels OR axis + gridlines, not both.
   - Use data labels when: there are few data points and exact values matter
   - Use gridlines when: there are many data points and relative position matters more than exact values
   - For bar charts: place labels inside the bar (for long bars) or just outside (for short bars), left-aligned
   - For line charts: label only the final value, or highlight specific notable points
   - Format: use the same number formatting as the axis (1 decimal place if axis uses 1)

4. Callout annotations (highlighting specific insight):
   - Use sparingly: maximum 2–3 annotations per chart
   - Format: brief text (5–10 words) + arrow pointing to the relevant data point or region
   - Content: explain WHY this point is notable, not just WHAT the value is
   - Example: 'Spike caused by holiday campaign (Dec 15–Jan 3)' is better than 'Peak value: 42,000'

5. Reference lines and bands:
   - Target / goal line: show with a dashed line, labeled directly on the line
   - Historical average: light dashed line
   - Confidence interval or forecast range: semi-transparent shaded band, not heavy borders
   - Crisis or event periods: shaded background band with a text label at the top

6. Legend placement:
   - Prefer: direct labeling at the end of each line / top of each series (no separate legend)
   - If legend is needed: place inside the plot area (top-right or bottom-right)
   - Never: use a legend positioned below a wide chart that requires eye travel

7. What NOT to annotate:
   - Every data point (creates noise, defeats the purpose)
   - Obvious features the viewer can see clearly
   - Multiple overlapping annotations in the same chart region

Return: title and subtitle for this specific chart, axis label specification, data label strategy, callout annotation text, and legend placement decision.